While sportswriters frequently bemoan the sheer number of transfers in college basketball, the notion that all the players leaving programs is always terrible for the program they're leaving... well, that's really debatable. Where attrition hurts is when star players (or potential star players) leave. Where it shouldn't hurt is when replacement level or worse players are leaving the program. It does end up hurting some programs just because the coach replaces the players who left with guys who are the same caliber of player (or worse), trapping the program in perpetual mediocrity until the coach gets fired.
But at least for 2016 and beyond, the Summerpocalypse of 2013 does not hurt the Vanderbilt basketball program.